There are a few paradigms I can think of off the top of my head that support it:

-The idea of 'temporary insanity' or 'diminished capacity' in our legal system. When invoked, it normally asserts that a situation was so overwhelming that the subject couldn't react as they normally would. The 'heat of passion' and all that. This implies that generally, we can control our reactions to most things, and uncontrollable reactions are the exception.

-The field of cognitive behavioral therapy, which does has scientific evidence of effectiveness [0], see cites. Perhaps 'control your reaction to anything' is less-than-supported in the case of CBT, but combined with point 1 that should be more than enough to get you started.

[0] http://en.wikipedia.org/wiki/Cognitive_behavioral_therapy#Ev...